Today's energy system is dependent only on hydrocarbons, especially oil, but increasingly also natural gas. Eighty per cent of the current global energy supply is of fossil origin.Gas hydrates (clathrates) are ice-like compounds in which gas molecules are held in crystalline cages formed by water molecules. They are widespread in areas of permafrost and in the continental margins where pressure and temperature conditions are appropriate for their formation. Methane hydrates are an energy source of potentially staggering magnitude compared with other known hydrocarbon deposits. This type of energy resources can be used as alternate fuel.A variety of gas hydrate research programs are currently underway in different parts of the world, and a listing of all of them is beyond the scope of this article. For Students and research scholars involved in alternate energy exploration this book will be very useful.